Electrical connector crimping tool



M. POLIDORI Oct. 7, 1969 ELECTRICAL CONNECTOR CRIMPING TOOL 3Sheets-Sheet 1 Original Filed June 22, 1964 I [v VENTOR MARIO P'OLIDORlOct. 7, 1969 M. POLIDORI ELECTRICAL CONNECTOR CRIMPING TOOL OriginalFiled June 22, 1964 3 Sheets-Sheet 7:

INVEVIURv mnmo POLIDOP\ Oct. 7, 1969 M. POLIDORI ELECTRICAL CONNECTORCRIMPING TOOL Original Filed June 22, 1964 3 Sheets-Sheet 3 'VENTOR.

POLIDORI United States Patent ()ii 3,470,728 ELECTRICAL CONNECTORCRIMPING TOOL Mario Polidori, Pennsauken, N.J., assignor to AMPIncorporated, Harrisburg, Pa.

Original application June 22, 1964, Ser. No. 376,941, now Patent No.3,322,887, dated May 30, 1967. Divided and this application Apr. 13,1967, Ser. No. 630,686

Int. Cl. B21f 15/06; B21d 17/02 US. Cl. 72-410 4 Claims ABSTRACT OF THEDISCLOSURE A crimping tool for crimping an electrical connector onto asupport member and a conductive wire, the tool provided with jaw memberspivotally connected together for movement toward and away from eachother, crimping means carried by the jaw members with each of thecrimping means having an elongated crimping area and spaced crimpingsections extending outwardly therefrom, the spaced crimping sections ofone crimping means being offset with respect to the spaced crimpingsections of the other crimping means and these spaced crimping sectionmeshing with each other upon the jaw members being moved into a crimpingposition by operating means connected thereto with the crimping meansbeing moved toward each other in a substantially parallel manner.

CROSS REFERENCE This invention is a division of US. Patent application,Ser. No. 376,941, filed June 22, 1964, now US. Patent No. 3,322,887.

This invention relates to crimped electrical connections, and moreparticularly to connector elements and tools for the formation thereof.In the formation of electrical connections, it is customary to enclosewire ends in an electrically-conductive metal ferrule. The presentinvention discloses this type of connector element which simultaneouslygrips a support means after it has been mechanically and electricallycompressed onto wires by a suitable crimping tool.

A spring leaf is used to bias carbon armature brushes against acommutator. One surface of the connector element presses against thebrush so that current is carried from the armature through the brush tothe connector element and subsequently to the wire.

In the art of armature-brush rigging, and particularly to brushes whichare radially applied to the commutator, the brush rigging must fulfillthe following requirements:

(1) The brushes must be held firmly against the commutator by a springmember (spring leaf and connector element in this case) but allowed tofollow any irregularity in the contour of the commutator without jumpingaway.

(2) All of the parts involved must be firm and strong so that thebrushes will not chatter as a result of excessive vibrations while themachine is running.

(3) The connector element must be capable of remaining mechanicallytight at all times although there is a differential in the expansion ofsteel and the metal of the connector element during temperature changes.

It is, therefore, a primary objective of the present invention toprovide a connector element which is capable of being cold-forged onto aspring leaf support means with at least one solid or stranded conductorwire compressed therebetween. A further object is the provision of aconnection whereby a softer connector element will deform around aharder support means as a result of crimping pressures from a tool.Another object is to provide a connection having large contact surfacesbetween the crimped ferrule and the spring leaf so that the ferrule will3,470,728 Patented Oct. 7, 1969 frictionally engage the spring leaf andgive added tensile strength to the connection. Another object is that ofproviding the combination of a closed ferrule connector element, largesurface engaging area, and a cold-forged con nection. Another object isto provide a tool head and die set for crimping the electricalconnector. Another object is to provide a die set for crimping theelectrical connector, which attaches to a scissor action tool head andwhich closes into the connector element in a straight-line path. Anotherobject is to provide a new method for obtaining an electricalconnection.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich .there is shown and described an illustrative embodiment of theinvention; it is to be understood, however, that this embodiment is notintended to be exhaustive nor limiting of the invention but is given forpurposes of illustration and principles thereof and the manner ofapplying it in practical use so that they may modify it in variousforms, each as may be best suited to the conditions of a particular use.

FIGURE 1 is a perspective view of a connection according to the presentinvention;

FIGURE 2 is a perspective view of the head of a crimping tool whichforms the connection of FIGURE 1;

FIGURE 3 is a view of the present tool head in position in a tool;

FIGURE 4 is a top plan view of the connection of FIGURE 1;

FIGURE 5 is a side elevational view of the connection of FIGURE 1 inengagement with a brush;

FIGURE 6 is an end view of FIGURE 4;

FIGURE 7 is an exploded perspective view of the connection elementsbefore crimping;

FIGURE 8 is a side elevational view of the tool head in the openposition; and

FIGURE 9 is a view similar to that of FIGURE 8 but showing the tool headclosed.

Referring now to the drawings and particularly to FIG- URE 7, theconnector element includes a closed rectangular-shaped ferrule 2 formedfrom electrically-conductive malleable metal, such as, copper, an alloythereof, or the like. It may be rolled up from a sheet metal blank withits seam brazed, it may be reformed from cylindrical tubing, or it maybe formed in any suitable and conventional manner. Ferrule 2 has apassageway 4 therethrough to receive a wire 6 and a spring leaf 8.

Compacting or crimping of the ferrule 2, spring leaf 6 and wires 8 isaccomplished by a die set D which includes an indenter 10 and a nest12.. Die set D is appropriately affixed to head H of a preferably airoperated tool T, FIGURE 3, of the type completely shown and described inUS. Patent No. 2,684,003, which is assigned to the present assignee.While an air or hydraulic-actuated tool is preferable in this casebecause of excessive crimping pressures needed and because of productionline techniques, it should be noted that head H may be adapted to fitinto a manually-operated tool of the type shown and described in US.Patent application, Ser. No. 420,586, filed Dec. 2, 1964, and assignedto the present assignee. Indenter 10 and nest 12 close onto ferrule 2 ina straightline path (straight action), FIGURE 2, :as opposed to thenormal arcuate path (scissor action) of a scissor action tool.

Nest 12 constitutes one-half of the die set and includes a fioor surface14 onto which the connector element rests in the tool. On one end offloor 14 is a locating block 16 and another locating block 18 as bestseen in FIGURE 8. Ferrule 2 abuts block 16 and the end of the springleaf 8 abuts block 18 when they are placed into the die set to becrimped in order to properly locate the ferrule along spring leaf 8.

Two crimping members 20 are positioned along each side of floor 14 indiametrical relationship and they extend outwardly therefrom. Members 20have angled surfaces 20' which engage limited portions of the bottomouter edges of ferrule 2 when the connector element is crimped. Theseportions are shown by 22, 24, 26 and 28 in FIG- URES 1, 4, and 6. Nest12 has arcuate-shaped slots 30 and 32 below floor 14 through which a pin33 passes in order to hold the nest on tool head H. Nest 12 also has twoguide posts 34 and 36, the extending ends of which slidably projectthrough corresponding holes in indenter as shown.

Indenter 10 constitutes the other half of die set D and is pinned to theupper jaw of the tool head H by means of a pin 38 passing througharcuate-shaped slots 40 and 41 in a manner similar to that of slots 30,32 and pin 33. Indenter 10 is located in diametrical relationship withrespect to nest 12 and is positioned with respect thereto by means ofguide posts 34 and 36. Indenter 10 includes a rectangular member 42longitudinally disposed in its central section as illustrated in FIGURES8 and 9. Member 42 engages the top surface of ferrule 2 and compressesthat portion of the ferrule onto the wires and spring leaf duringcrimping.

Three outwardly extending crimping members 44 with angled surfaces 44'thereon are positioned along each side of the crimping area of indenter10 and they are alternately spaced with respect to crimping members onadjacent nest 12. During crimping, members 20 and members 44 indentferrule 2 along opposite sides thereof in a staggered manner. Theindenting line of force is at right angles to the longitudinal axis offerrule 2 because of the straight-line die action.

The indenter and nest are converted from scissor action to straight-lineaction by means of the pin 33 and slots and 32 of the nest and pin 38and slots and 41 of the indenter in conjunction with guide posts 34 and36. Surfaces56 of indenter 10 engage surfaces 58 of nest 12 when the dieset has been moved to its closed position in order to limit the movementof these elements toward each other.

OPERATION Spring leaf 8 and wires 6 are inserted into ferrule 2 in themanner shown by FIGURES 1 and 7. Wires 6 are positoned so that theirforward ends are appropriately spaced from the front of spring leaf 8.This sub-assembly is placed into die set D so that lower forward edge 46of ferrule 2 abuts locating block 16 and forward edge 48 of spring leaf8 abuts locating block 18. The connection elements are now positioned inthe die set D for crimping.

As the tool closes onto the connector element, rectangular member 42 onindenter 10 pushes the ferrule downwardly against nest 12. At this time,the angled surfaces 44 on crimping members 44 engage the top edges offerrule 2 and compress the ferrule downwardly and inwardly in areas 50as illustrated in FIGURES 1 and 6. As indenter 10 bottoms into nest 12,angled surfaces 20' on crimping members 20 engage opposite edges offerrule 2 in staggered relationship to crimping members 44. Crimpingmembers 20 push areas 22, 24, 26 and 28 of ferrule 2 upwardly andinwardly towards the spring leaf as illustrated in FIGURE 4.

The forces of crimping members 20 and 44 in conjunction with thecrimping forces from rectangular member 42 and floor 14 compress ferrule2 onto wires 6 and spring leaf 8. These combined forces also cause thetop surface of ferrule 2 to bow inwardly as at 54, FIGURES 1 and 6, andthereby tighten the ferrule onto the wires and spring leaf to effect anexcellent mechanical and electrical connection.

The above crimping action causes large interfaces to occur between theconnector element and the spring leaf at the top and bottom thereof andinterfacial angles between the inside of ferrule 2 and the edges ofspring leaf 8. By this means, the ferrule is frictionally held onto thespring leaf especially when the material of the spring leaf is harderthan that of the ferrule.

The above crimp features in conjunction with a closed ferrule will causethe ferrule to tighten onto the spring leaf when the connector elementis subjected to temperature changes, even though there is a differentialof expan sion between steel and the metal of the ferrule.

In cases where the material of the spring leaf 8 is capable of beingindented, crimped areas 22, 24, 26, 28 and 50, which result fromcrimping members 20 and 44, will indent the edges of the spring leaf.This causes material of the ferrule to flow into the indents and provideadditional tensile for the connection.

It will, therefore, be appreciated that the aforementioned and otherdesirable Objects have been achieved; however, it should be emphasizedthat the particular embodiment of the invention, which is shown anddescribed herein, is intended as merely illustrative and not asrestrictive of the invention.

The invention is claimed in accordance with the following:

1. A crimping tool for compressing a ferrule member onto a membercomprising jaw members, pivot means pivot means pivotally connectingsaid jaw members together, crimping-die means on said jaw members, oneof said crimping-die means defining a nest including a floor surfaceonto which the ferrule member rests and crimping members positionedalong each side of said floor surface in opposed relationship, the otherof said crimping-die means having an indenter in alignment with saidfloor surface and crimping members positioned along each side of saidindenter in opposed relationship, the crimping members of said onecrimping-die means being offset with respect to the crimping members ofthe other crimping-die means so that these crimping members mesh witheach other, means for moving said jaw members toward and away from eachother, and means on said jaw members and said crimping-die meansconstraining said crimpingdie means to straigh -line movement when saidjaw members are moved about said pivot means.

2. A crimping tool according to claim 1 wherein said one crimping-diemeans includes locating means to locate said ferrule member on saidfloor surface.

3. A crimping tool according to claim 1, wherein said crimping membershave angled surfaces which are angled away from said floor surface andsaid indenter.

4. A crimping tool according to claim 1 wherein said constraining meanscomprises pivot pins and slots in which said pivot pins are disposedbetween said jaw mem bers and said crimping-die means and guide postsmateable with openings on said crimping-die means.

References Cited UNITED STATES PATENTS 2,692,384 10/1954 Pollock 72-4072,992,576 7/1961 Evans et al. 72-410 RONALD D. GREFE, Primary ExaminerUS. Cl. X.R.

